1978 CB750, Burning 1 Quart of Oil in about 800 miles

[honda000019]

Hi I'm Ryan. I recently bought this restored 1978 CB 750 SOHC from a retiree who collects and restores them. I ran into trouble on day 1 though when a the main fuse blew. Others issues include trouble with the float bowls if I don't turn the gas off and my biggest concern - the huge amounts of oil that it goes through. I put in almost a quart when I got it to put the dipstick on full. 800 miles later here goes another quart. I was warned it would go through "a little oil" but this is pretty much a new oil change every 2 thousand miles by itself.

He had modified a few things such as; linked the carburetors together and put in a different camshaft. He said to me that the reason it's burning oil is that the new camshaft rides the valve guides differently and they are leaking.

So I take it too a shop and ask them what it will cost for a valve job and they say it's about 2000 dollars. I cannot afford that at this point in time, so I was wondering if anyone has the time or desire to layout the process, tools, and parts I need to do it myself if at all possible or if the mechanic was just throwing me a super high estimate and I should look elsewhere? I've no problem doing it myself if it's a relatively simple job.

 

[dirtdigger]

The f2 motors (black 750 motors) had problems with the exhaust guides wearing because of valve angle changes that had to be done to accomodate the larger valves the the K motors which caused increased wear on the guides. You need to have a shop do the work because after the guides are replaced you have to have a valve job done. $2000 is veryhigh in my opinion. You can send the head to APE www.aperaceparts.com. They can do a complete rebuild on the f2 head for $700. They are hands down the best motorcycle machine shop out there and they are an origninal shop that was around when the 750 first came out. They are doing work on my f2 head right now.

Beings you dont know the history of the bike you could be burning oil through the rings also. Rings could be stuck from setting for years or the motor could have been stuck at one time and this guy freed it up without doing a rebuild.

 

[K2750tracy]

if that is a pic of the bike you have the PO changed the carbs too, the 78 F2 should have the key hole carbs not the round tops on that bike, not bad carbs just not correct. by the way that's a very nice F2, wish the one I just got was half that clean.